Our Oysters

Our oysters, Crassostrea Gigas, sourced from our own hatchery, stem genetically from the original brood stock introduced to Ireland in the early 1970s under strict quarantine protocol in collaboration between University College Galway’s Shellfish Research Programme and the U.K. Ministry of Fisheries. The stock was sourced from British Columbian waters, where environmental and climatic conditions match closely those of the Atlantic coast of Ireland.

Its suitability to Ireland’s Atlantic coast was confirmed through a Research and Development programme over a ten year period. A study of the genetics of the stock by the University zoology dept. confirmed excellent breeding potential and also concluded that it differed substantially from the strain being farmed in France.

Wild Atlantic Oyster Hatchery

Growing the Oysters to Maturity

Oyster are transferred from the nursery to oyster bags, which are then attached to trestles placed in long lines on a protected sandy beach. These bags are turned and shaken regularly throughout the growing season from March to October. The bags are taken ashore a number of times during the season, the oysters removed from the bags, graded and returned to bags at ever lower densities, as they increase in size.

Oyster Nursery

The photographs show a floating upwelling nursery system, known as a Flupsy which is designed to ensure that the seed oysters are provided with a steady supply of nutrient rich sea water, drawn up through the fine mesh bottom of the holding sections. They remain here until they reach 10mm grade size

Growing the Oysters to Maturity

Oyster are transferred from the nursery to oyster bags, which are then attached to trestles placed in long lines on a protected sandy beach. These bags are turned and shaken regularly throughout the growing season from March to October. The bags are taken ashore a number of times during the season, the oysters removed from the bags, graded and returned to bags at ever lower densities, as they increase in size.

Attaching Oyster Bags to Trestles

At regular intervals throughout the growing season, bags of oysters are taken from trestles by tractor, are unloaded, graded by physical size (length and width), and returned to bags, to be put back on trestles to continue growing:

Wild Atlantic Oyster Production

Final Grading for Packing

Final Grading for Packing

As the oysters mature the bags are taken ashore and emptied into a hopper from which they are conveyed, automatically, through a high-powered washer, to a circular grader which sorts them into a range of sizes, depending on their weight. There are eight grades and two packing options, as follows:

Note: Sample quantities of 12 pieces per basket are packed, on demand
In addition to the five basic grades, we grow larger oysters, as shown in the table below.

Customers requiring these sizes are advised that they may not be always in stock. To ensure a steady supply of large oysters, we engage with customers regarding their projected needs. Our farmers will then set aside sufficient stocks of smaller oysters at the start of the growing season in March, so that they will grow on to the customer’s requirements for supply the following Autumn.

Grade

Size

Packing in 25Kg Polystyrene Fish Box
(Average)

Packing in Wooden Chip Baskets(Typical)

N0XXL

200g+

100 pieces per box

12, 24 pieces per baske

NOXL

180 – 200g

130 pieces per box

24 pieces per basket

NOL

150 – 180g

150 pieces per box

24 pieces per basket

Depuration

All oysters are supplied live and ready for consumption. To ensure the safetyof the oysters for human consumption, they are placed for a minimum of forty eight hours in depuration tanks. These tanks contain sea water which is continuously circulated through UV filters, to remove all traces of microbial infection, prior to packing for delivery to the market. Skimmers are added, to remove all suspended particles from the water, and the water is further disinfected using ozone. The water may be heated in Winter, to help combatinfection, and cooled in Summer, to ensure that the oysters are in prime condition for delivery to the customer.